The present disclosure relates to an electronic apparatus such as a television (TV)-broadcast receiver, a method for adjusting configuration sections employed in the electronic apparatus and ICs (Integrated Circuits) implementing the electronic apparatus.
A variety of adjustments are typically required in a front-end section of a tuner employed in a TV-broadcast receiver. The adjustments include the adjustment of the tuning frequency and gain of a tracking filter employed in a tuning circuit of the front-end section and the adjustment of an image-interference removal characteristic of a band-pass filter provided in the front-end section for a video intermediate frequency.
For example, a variable-capacitance diode can be generally implemented in an IC so that a uniform characteristic can be obtained for all variable-capacitance diodes. However, a coil cannot be implemented in an IC. Thus, the inductance undesirably varies from coil to coil. As a result, since the inductance of the coil employed in a tuning circuit to serve as a coil for tuning varies from circuit to circuit, the tuning frequency of the tuning circuit may inevitably contain a tracking error.
In the past, in order to get rid of a tracking error, an air-core coil was adjusted manually. However, since the air-core coil has a large size, the tuning circuit employing the air-core coil cannot be made compact. In addition, the need to manually adjust the air-core coil raises a problem by itself.
For example, as a typical solution to this problem, Japanese Patent Laid-open No. Hei 11-168399 proposes a receiver capable of automatically getting rid of tracking errors by making use of tracking-error elimination data stored in advance in a nonvolatile memory to serve as data to be used for getting rid of a tracking error contained in the tuning frequency for every reception frequency. To put it concretely, the tracking-error elimination data is supplied to a variable-capacitance diode to serve as data to be used for getting rid of a tracking error contained in the tuning frequency for every reception frequency.
That is to say, in an actual receiver, the tuning data to be supplied to the variable-capacitance diode for every reception frequency is adjusted in order to find an optimum value which maximizes the reception sensitivity. The optimum value is then stored in the nonvolatile memory in advance as pre-found adjusted data for getting rid of a tracking error. Then, the pre-found adjusted data provided for a reception frequency selected by the user is read out from the non-volatile memory to be used as data for getting rid of the tracking error in an automatic tracking-error adjustment process.
Meanwhile, tracking errors of the front-end circuit employed in a receiver are different from tracking errors of the front-end circuit employed in another receiver. Thus, pre-found adjusted data to be stored in a nonvolatile memory associated with the front-end circuit employed in a receiver is also different from pre-found adjusted data to be stored in a nonvolatile memory associated with the front-end circuit employed in another receiver. Accordingly, if a front-end circuit is implemented as an IC, it is possible to conceive a configuration in which a nonvolatile memory associated with the front-end circuit is embedded in the same IC as the front-end circuit and, then, the pre-found adjusted data provided for a reception frequency selected by the user is read out from the non-volatile memory to be used as data for getting rid of the tracking error in an automatic tracking-error adjustment process.
It is necessary to adjust not only the front-end circuit, but also other configuration circuits employed in a TV-broadcast receiver in some cases due to the fact that each of the other configuration circuits includes a resistor with a resistance varying from circuit to circuit as well as a capacitor with a capacitance also varying from circuit to circuit. In such a case, if another configuration circuit is implemented as an IC, it is possible to conceive a configuration in which a nonvolatile memory associated with the other configuration circuit is embedded in the same IC as the other configuration circuit.
However, for a TV-broadcast receiver, it is not economical to provide the configuration in which a nonvolatile memory associated with any of configuration circuits including the front-end circuit is embedded in the same IC as the configuration circuit. Such a configuration raises a problem of a high cost of manufacturing the TV-broadcast receiver.